Getting printouts when writing macro-level decoders

stuff.scala

// It's a bit complex because if you throw an error you usually don't get the result
// i.e. the place where the decoder is summoned returns the error because no decoder can be summoned from there
// [error] -- Error: /Users/aleiof/git/dotty_test/quill-sql/src/test/scala/io/getquill/QueryTest.scala:31:26 
// [error] 31 |      val result = ctx.run(q)
// [error]    |                   ^^^^^^^^^^
// [error]    |                   Decoder could not be summoned during query execution

// if you use report.warning and return something you usually get it
  def decode[T: Type, ResultRow: Type](index: Expr[Int], resultRow: Expr[ResultRow])(using Quotes): Expr[T] = {
    import quotes.reflect._
    // if there is a decoder for the term, just return the term
    Expr.summon[Mirror.Of[T]] match
      case Some(ev) =>
        // Otherwise, recursively summon fields
        ev match {
          case '{ $m: Mirror.SumOf[T] { type MirroredElemLabels = elementLabels; type MirroredElemTypes = elementTypes }} =>
            // First make sure there is a column resolver, otherwise we can't look up fields by name which 
            // means we can't get specific fields which means we can't decode co-products
            Expr.summon[GenericColumnResolver[ResultRow]] match
              case None => report.warning(s"Need column resolver for in order to be able to decode a coproduct but none exists for ${Format.TypeOf[ResultRow]}")
              case _ =>
          
// [warn] -- Warning: /Users/aleiof/git/dotty_test/quill-sql/src/test/scala/io/getquill/QueryTest.scala:31:26 
// [warn] 31 |      val result = ctx.run(q)